Optical transmitter and optical communication system

The optical transmitter has a feature that the transmitter comprises a light-emitting device, an optical splitter, a dispersion controller including a first dispersion generator and a waveform monitor, and a processing unit. The optical splitter splits light emitted from the light-emitting device, and guides one of split light into the first dispersion generator. The first dispersion generator adds dispersion, an amount of which is predefined by the processing unit so as to reflect dispersion of the optical path to the receiving station, to the split light and outputs dispersed light to the waveform monitor. The processing unit maintains the dispersed light output from the dispersion generator to have a predetermined quality.